Virus

A virus is an infectious agent whose genome replicates only inside host cells. It consists of genetic material enclosed in a protein coat, sometimes surrounded by a membrane.

Viral replication: The process by which a virus copies its genome and produces new viral particles inside host cells. Replication inside host cells is the defining feature of viruses.
Viral genome: The DNA or RNA molecule that stores a virus's genetic information. Its genome determines how a virus encodes and copies its components.
Vaccination: The process of inducing immune protection against a pathogen or disease. Vaccines prepare immune defenses to recognize viral infection.
Bacterium: A single-celled microorganism without a membrane-bound nucleus. Bacteria are cellular organisms that can reproduce without entering another cell.
Viral disease: A disease caused by infection with a virus. Viral replication can damage tissues or disrupt their function.
Viral entry: The steps by which a virus attaches to a host cell and delivers its genome into it. Entry begins the intracellular cycle that allows viral replication.
Capsid: The protein shell that encloses and protects a virus's genetic material. The capsid is the central structural component of many virus particles.
Antiviral drug: A medicine that inhibits viral infection or replication. Antiviral drugs target steps in the viral life cycle.
Prion: An infectious misfolded protein that propagates its shape without a nucleic-acid genome. Prions are infectious agents but lack the genomes found in viruses.
Emerging infectious disease: An infection that is newly appearing in a population or rapidly increasing in incidence or range. Changes in viruses and their hosts can produce newly spreading infections.

Linked from 29 pages